The present invention relates to an imaging device including an autofocus function to control a focus lens to automatically set the lens to an appropriate in-focus position and a wide dynamic range function to enable a shooting operation of a scene having a wide dynamic range.
A technique of the conventional art in the field related to the present invention has been described in, for example, JP-A-2002-323649. According to the technique, a problem resides in that to create a wide dynamic range image by combining with each other a plurality of screens obtained by shooting one subject under a plurality of exposure conditions, autofocus control is conducted for the subject in various luminance areas. To solve the problem, by disposing a focus voltage selection unit to selectively output, as focus voltages to be referred to by an autofocus control unit, a plurality of focus voltages detected in a plurality of images associated with different exposure conditions, autofocus control is possible for various subjects shot at an appropriate signal level in the respective images shot under different exposure conditions. By further disposing a unit to normalize a plurality of focus voltages, influence of a change in the exposure condition upon the focus voltage is removed, to thereby make it possible to conduct autofocus control independent of the exposure condition.
Further, WO03/102636 describes a technique in which to provide a variable focus lens operating at a frame rate of a high-speed visual system and a control device of the variable focus lens, there is provided a variable focus lens 10 including a container 11 filled with liquid. The container 11 includes a pressure transmission section 15 which makes contact with an actuator 14 to transmit vibration thereof to an associated section and two light transmission sections 12 and 12 on a light incidence surface and a light emission surface. On at least one of the light incidence and emission surfaces, there is disposed a surface section capable of changing in the optical axis direction in the form of projections and depressions in response to a change supplied via the liquid from the pressure transmission section 15. The surface section has an area of s and the pressure transmission section 15 has an area of S, and the ratio therebetween (s/S) is equal to or less than a predetermined value. In response to a change in the actuator 14, the surface section changes, to thereby change the focal length or distance.